[TOSA] Fix Tensor.hacked_twin to support diff size indexes (#3547)

- Broadcasts index list tensors
- Adds torch.nn.Unfold test

Signed-off-by: Suraj Sudhir <suraj.sudhir@arm.com>

lib/Conversion/TorchToTosa/TorchToTosa.cpp

@@ -3797,13 +3797,126 @@ LogicalResult ConvertAtenOp<AtenIndexTensorHackedTwinOp>::matchAndRewrite(
       indicesTfConcatTensors.push_back(indicesTfOneDim.getResult());
     }
 
-    // Right now only support multiple indexes with same shape
-    // TODO for different shape multiple indexes, add broadcast_to for small
-    // shape
+    auto getRankExtendedShape =
+        [](SmallVector<int64_t> inputShape,
+           SmallVector<int64_t> maxRank1DimShape) -> SmallVector<int64_t> {
+      SmallVector<int64_t> rankExtendedShape(maxRank1DimShape);
+      auto inputRank = inputShape.size();
+      auto maxRank = maxRank1DimShape.size();
+      auto startIdx = maxRank - inputRank;
+      for (size_t i = startIdx; i < maxRank; i++) {
+        rankExtendedShape[i] = inputShape[i - startIdx];
+      }
+      return rankExtendedShape;
+    };
+
+    bool hasDiffShapedIndexes = false;
     for (auto indexShapeOneDim : indexesShape) {
       if (!llvm::equal(indexesShape[0], indexShapeOneDim)) {
-        return rewriter.notifyMatchFailure(
-            op, "unimplemented: Only support multi indexes with same shape");
+        hasDiffShapedIndexes = true;
+        break;
+      }
+    }
+
+    if (hasDiffShapedIndexes) {
+      int64_t maxRank = 1;
+      for (auto idxRank : indexesRank) {
+        if (idxRank > maxRank)
+          maxRank = idxRank;
+      }
+      // Tensor shape of max rank, each dim being 1
+      SmallVector<int64_t> maxRank1DimShape;
+      for (int i = 0; i < maxRank; i++)
+        maxRank1DimShape.push_back(1);
+      // Tensor shape of max rank, each dim being the max dim.
+      SmallVector<int64_t> maxRankMaxDimShape(maxRank1DimShape);
+
+      auto updateMaxRankMaxDimShape =
+          [&](SmallVector<int64_t> broadcastedShape) -> LogicalResult {
+        for (size_t i = 0; i < maxRankMaxDimShape.size(); i++) {
+          // check for malformed index tensors
+          if (broadcastedShape[i] != 1 && maxRankMaxDimShape[i] != 1 &&
+              maxRankMaxDimShape[i] != broadcastedShape[i]) {
+            return failure();
+          }
+          if (broadcastedShape[i] > maxRankMaxDimShape[i])
+            maxRankMaxDimShape[i] = broadcastedShape[i];
+        }
+        return success();
+      };
+
+      for (size_t i = 0; i < indexesRank.size(); i++) {
+        // Reshape all index tensors to same maxRank
+        auto idxRank = indexesRank[i];
+        auto unreshapedIdxTensor = indicesTfConcatTensors[i];
+        SmallVector<int64_t> broadcastedShape =
+            getRankExtendedShape(indexesShape[i], maxRank1DimShape);
+
+        if (idxRank < maxRank) {
+          auto idxType =
+              dyn_cast<RankedTensorType>(indicesTfConcatTensors[i].getType());
+          // indicesTfConcatTensors has a trailing [1] dim for the final concat.
+          auto broadcastedShapeTf(broadcastedShape);
+          broadcastedShapeTf.push_back(1);
+          auto reshapeOutputTy = RankedTensorType::get(
+              broadcastedShapeTf, idxType.getElementType());
+          // Update the tensor array with the max rank-extended form
+          indicesTfConcatTensors[i] = rewriter.create<tosa::ReshapeOp>(
+              op->getLoc(), reshapeOutputTy, unreshapedIdxTensor,
+              rewriter.getDenseI64ArrayAttr(broadcastedShapeTf));
+        }
+
+        // Construct the max rank broadcasted form of all index tensors with
+        // each index tensor.
+        if (updateMaxRankMaxDimShape(broadcastedShape).failed()) {
+          return rewriter.notifyMatchFailure(
+              op, "Malformed index tensors that have mismatched dim shapes");
+        }
+
+        // Every index now has the same rank but not yet same shape until
+        // tosa.tile below.
+        indexesShape[i] = broadcastedShape;
+        indexesRank[i] = maxRank;
+      }
+
+      auto getTileOpShape = [&](SmallVector<int64_t> indexShape,
+                                SmallVector<int64_t> &tileOpShape) -> bool {
+        bool needsTiling = false;
+        for (size_t i = 0; i < indexShape.size(); i++) {
+          if (1 == indexShape[i]) {
+            tileOpShape.push_back(maxRankMaxDimShape[i]);
+            needsTiling = true;
+          } else {
+            tileOpShape.push_back(1);
+          }
+        }
+        return needsTiling;
+      };
+
+      // Use tosa.tile to broadcast in multiple dims so all index tensors have
+      // the same shape. This materializes new tensors.
+      for (size_t i = 0; i < indexesRank.size(); i++) {
+        SmallVector<int64_t> tileOpShape;
+        bool needsTiling = getTileOpShape(indexesShape[i], tileOpShape);
+
+        if (needsTiling) {
+          auto idxType =
+              dyn_cast<RankedTensorType>(indicesTfConcatTensors[i].getType());
+          // indicesTfConcatTensors has a trailing [1] dim for the final concat.
+          auto maxRankMaxDimShapeTf(maxRankMaxDimShape);
+          maxRankMaxDimShapeTf.push_back(1);
+          auto tileOpShapeTf(tileOpShape);
+          tileOpShapeTf.push_back(1);
+          auto tileOutputTy = RankedTensorType::get(maxRankMaxDimShapeTf,
+                                                    idxType.getElementType());
+          auto reshapedIdxTensor = indicesTfConcatTensors[i];
+          indicesTfConcatTensors[i] = rewriter.create<tosa::TileOp>(
+              op->getLoc(), tileOutputTy, reshapedIdxTensor,
+              rewriter.getDenseI64ArrayAttr(tileOpShapeTf));
+        }
+
+        // Every index tensor now has the same rank and shape
+        indexesShape[i] = maxRankMaxDimShape;
       }
     }
 

projects/pt1/e2e_testing/xfail_sets.py

@@ -30,6 +30,7 @@ LINALG_XFAIL_SET = COMMON_TORCH_MLIR_LOWERING_XFAILS | {
     # this is added to check the torch.onnx.export -> import_onnx -> torch path
     "DeformConv2D_basic",
     "ReduceAnyDimFloatModule_basic",
+    "UnfoldModule_basic",
 }
 
 LINALG_CRASHING_SET = {
@@ -1983,6 +1984,8 @@ TOSA_PASS_SET = {
     "TorchPrimLoopForLikeTensorArgModule_basic",
     "RenormModuleFloat32NegativeDim_basic",
     "RenormModuleFloat32_basic",
+    "IndexTensorStaticContiguousWithNoneModule_basic",
+    "IndexTensorStaticNonContiguousWithNoneModule_basic",
 }
 
 MAKE_FX_TOSA_PASS_SET = (
@@ -2750,6 +2753,7 @@ ONNX_XFAIL_SET = {
     "ReduceAnyFloatModule_basic",
     "ReduceMaxAlongDimUnsignedInt_basic",
     "ReduceMinAlongDimUnsignedInt_basic",
+    "UnfoldModule_basic",
 }
 
 if torch_version_for_comparison() < version.parse("2.3.0.dev"):
@@ -3189,7 +3193,6 @@ FX_IMPORTER_TOSA_XFAIL_SET = {
     "IndexSelectWholeTensorModule_basic",
     "IndexTensorDyanmicInputContiguousWithNoneModule_basic",
     "IndexTensorDyanmicInputNonContiguousWithNoneModule_basic",
-    "IndexTensorHackedTwinMultiInputNonContiguousMultipleStaticDims_basic",
     "IndexTensorMultiInputContiguousCenter_basic",
     "IndexTensorMultiInputContiguousOneDimDynamic_basic",
     "IndexTensorMultiInputNonContiguousDynamic_basic",

projects/pt1/python/torch_mlir_e2e_test/test_suite/basic.py

@@ -5646,3 +5646,27 @@ def AtenKthvalueFloat64DynamicDimsModule_basic(module, tu: TestUtils):
     module.forward(
         torch.randperm(4 * 2 * 8 * 3, dtype=torch.float64).reshape(4, 2, 8, 3)
     )
+
+
+# ==============================================================================
+
+
+class UnfoldModule(torch.nn.Module):
+    def __init__(self):
+        super().__init__()
+        self.unfold = torch.nn.Unfold(kernel_size=(2, 3))
+
+    @export
+    @annotate_args(
+        [
+            None,
+            ([-1, -1, -1, -1], torch.float32, True),
+        ]
+    )
+    def forward(self, input):
+        return self.unfold(input)
+
+
+@register_test_case(module_factory=lambda: UnfoldModule())
+def UnfoldModule_basic(module, tu: TestUtils):
+    module.forward(tu.rand(2, 5, 3, 4))